Valtonus wrote: ↑Thu Mar 23, 2017 11:55 am
SuperBanshee wrote: ↑Thu Mar 23, 2017 5:42 am
According to the 1954 Federal Civil Defense Administration manual,
Scream-
Master touted a 20 horsepower 125 decibel
rotating siren however I've never been able to track down any further information on this siren. I'm very surprised the dual headed 500 would be tied to
Scream-
Master since every other
Scream-
Master I've seen photos of appeared to be factory-original designs. All I can think of is that
Scream-
Master was selling some Federal sirens alongside production of their own sirens. They did manufacture their own poles and mounting equipment which were fairly distinctive as the poles were metal instead of wood.
Thats interesting! Can I see your reference for the 125DB siren?
Get ready to enjoy a bit of what I go through when researching... LOL
The book is only available as a very limited preview, composed of "snippets". You can only view one snippet at a time but if you punch enough search terms in the little search box you can sometimes make out more of a page. It isn't practical to compile entire pages so you're often stuck going with just what can be found. The reason for this boils down to copyrights but I invite anyone who's really interested in siren research to contact the copyright holders for a complete copy. Here is a screenshot showing what I'm stuck with and where the reference popped up. They did not mention the 500-DHTT ("550AT", "500 Dual Head", CatDog, etc.) as a standalone Federal siren.

- The joys of research.
The 500-DHTT is a Federal product but the question was whether or not they were only made for
Scream-
Master and sold through them. Federal used to make sirens and siren parts for other clients, perhaps the most notable being W. S. Darley.
I have never once found a standalone Federal catalog mentioning a 500-DHTT but the following quoted information comes from an older topic revolving around Calhan, CO's siren, courtesy of reputable expert Adam Pollak:
I was going back trying to remember what the source was of the name "550" or "550-AT" for the dual-headed, rotating, dual-tone Federal siren, such as in Calhan, CO. The reason I ask is that I have something mentioning various warning devices (without pictures) and one of the listings is:
Federal Sign & Signal Corp. 500-DHTT Horizontal axis, bidirectional, 670 & 450 cps
DHTT would presumably be Dual-Head (DH), Dual-Tone (TT). The listed frequencies work out to essentially a 12/8 port siren, which is what the Calhan, CO siren sounds like. "TT" and "T" seem to be naming conventions used throughout various years by Federal. Most literature I've seen uses on "T" for dual-tone, but I have seen the "TT" before. Notably, Dane County, WI lists some of their sirens as "T" and some as "TT". Do any of you have more information on sirens like the Calhan, CO one being referred to as either a 550 or 500-DHTT?
CPS is "cycles per second" a largely-disbanded term for the unit of frequency now known as the Hertz. Federal waffled back and forth between using a single "T" or two "TTs" to note a two tone ("dual tone", "double tone" "dipsy doodle") siren. Depending who was writing what, you had a 1000TT, a 1000T, a 500-SHTT, a 500T, a 7TT, a 5T, or an SD-10, and then come the notations for three phase ("A") or single phase ("B")... go through some of the old catalogs that used to be on the main site and you'll see what I mean. Their naming conventions were never very consistent although I never found anything outside of the forum referring to a "550" or "550AT".
I feel it's compulsory to note I study sirens not only to learn more about them but also to share what I know with others who are interested. That's why I wanted to throw it all into a book later on once I found as much reputable information as possible. I'm not perfect but I'm proud of what I've managed to find over the past couple years, and I'm happier to share it with others who are interested. It was never meant to be an arms race nor do I want it to turn into some crazy competition... anyone who wants to do siren dirt-digging is welcome.
